HP E1328A, Руководство по обслуживанию, Страница: 52 / 70

Inspect the DAC for signs of abnormal internally generated heat such as
discolored printed circuit boards or components, damaged insulation, or
evidence of arcing. If there is damage, do not operate the DAC until you
correct the problem.
Checking Switches/Jumpers
Verify the logical address setting is set correctly (factory set at 72). See the
HP E1328A User’s Manual for information.
Testing the A1 Assembly
To test the A1 Assembly, remove mainframe power and remove the DAC
from the mainframe. Then, see table 8-2 for guidelines to isolate the
problem to a user-replaceable part.
Repair /
Maintenance
Guidelines
This section gives guidelines to repair and maintain the HP E1328A DAC,
including:
•
ESD precautions
•
Soldering printed circuit boards
•
Post-repair safety checks
ESD Precautions
Electrostatic discharge (ESD) may damage MOS, CMOS and other static
sensitive devices in the HP E1328A DAC. This damage can range from
slight parameter degradation to catastrophic failure. When handling DAC
assemblies, follow these guidelines to avoid damaging DAC components:
•
Always use a static-free work station with a pad of conductive
rubber or similar material when handling DAC components.
•
After you remove the DAC from the mainframe, place the DAC on
a conductive surface to guard against ESD damage.
•
Do not use pliers to remove a MOS or CMOS device from a
high-grip socket. Instead, use a small screwdriver to pry the device
up from one end. Slowly lift the device up, one pair of pins at a
time.
52 Service Chapter 8